UNITED STATES DEPARTMENT OF THE INTERIOR J. A. Krug, Secretary GEOLOGICAL SURVEY W. E. W rather, Director Bulletin 956 GEOLOGY AND ORE DEPOSITS OF THE LIBBY QUADRANGLE, MONTANA BY RUSSELL GIBSON WITH SECTIONS ON GLACIATION BY W. C. ALDEN AND PHYSIOGRAPHY BY J. T. PARDEE UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1948 For sale by tbe Superintendent of Documents, U. S. Government Printing Office, 'Washington 25, D. C. 857680 CONTENTS Page Abstract__ ______________________________________________________ 1 Introduction._____._.____-___-_-_-._-.-__--___----..---__-.-.___._ 2 Purpose of the investigation....___-_.___.______--_____-_-___._. 2 Field work and acknowledgments ___-_---___--__---___-_--_.___ 3 Previous work_______________________________________________ 3 Bibliography. _____.__________-_.___.___.._-.__-.________. 4 Geography_____________________________________________________ 5 Location and accessibility.--_-__--------------------_----_____- 5 Topography. ___________-____---_--_--____--_-----_-----_-_-_- 5 Climate and vegetation.. --____-____-__-----___--____________ 7 Bock formations_________________________________________________ 8 Sedimentary rocks.__-__-__--____-----_----_--_-_----_-_---.--- 8 Pre-Cambrian_ ____________---___-___---__-__..__---_____- 8 Belt series-__-__-__-___---____-_--_----_---__----__..-- 8 Prichard formation ________________________________ 10 Distribution __________________________________ 10 Thickness..._____..-_----___..___..___.. 10 Lithology._ .....................^........... 10 Ravalli formation________________________________ 11 Distribution. ___________ __-_-_-^--_____- ,11 Thickness ..................................^. 11 Lithology-_____. _ ____._._ ______ 12 Wallace formation.---..---...___.__-_-_-_---_._--_ 13 Distribution __________________________________ 13 Thickness. ______ .............^........ _____ 13 Lithology _____ _--_-_-_-_-__--__---__--_-_--_-. 14 Striped Peak formation___________________________ 16 Distribution __________________________________ 16 Thickness. _._._._______.----______-_._-.. 16 Lithology__ _-.___. .......................... 16 Libby formation_____.__.-__._______-___._._.___. 17 Distribution. ______-__-..____--__-__.____.___. 17 Thickness.,__.-...._..____.-__-_-____-.-____. 18 Lithology__...___________._________ 18 Paleozoic. .......................^................^....... 19 Cambrian. ___________________________________________ 19 Igneous rocks_--.__---_-__-___--__---_-_____------_---_---_.._ 20 Pre-Cambrian metadiorite sills._____________________________ 20 Size and distribution.__________________________________ 20 Composition __________________________________________ 21 Hornblende._-_____--____--__--__-_--__-_-_-_--_-_ 21 Plagioclase__-__-__-____ _ _.._ __._--__-.__ 23 Quartz_._________________________________ 23 Age _-_-_-__-___-_______-__-__-_-_____.___-___-____ 23 m IV CONTENTS Rock formations Continued Igneous rocks Continued Mesozoic (?) intrusive rocks____--<_-_-____-_____--_-__--_--_ 24 Stocks.__._..__.______..__-_-._.______________-__ 24 Dry Creek stock of quartz monzonite or granodiorite _ _ 24 Granodiorite stock on Granite Creek.________________ 28 Payne Creek stock of metadiorite__________________ 28 Hayes Ridge stock of quartz monsonite______-__-_-__ 29 Parmenter Creek stock of quartz monzonite__.____-__ 29 Syenite stock on Bobtail Creek___ __ _ _ ^ _ _._______._L_. 29 Dikes___-_-__-______----__-________________ 32 .. .. Distribution and relations._________________.:____^L: 32 Character-__-_--^----_______^____--_.^_-_____-____ 33 ....... .. Dikes closely associated with stocks._____________ 33 Dikes-not closely associated with stocks. ___- _____ 34 . Metamorphism_____________.______Ll_._---______l_^_-_ 35 . .... Autometamorphic alteration in the stocks. ^__-:_^-__._ 35 Relation of Dry Creek stock and Payne Creek stock to" '-' . Bull Lake fault_____________._______^___'i___'-37 .. .. Contact.metamorphism.__________________il"L_Ji_jl^- : 37 Age of the.stocks-.^-__ J.___. J._» a.-__________'__'i'"l"_;Jj_'-_i.__ 38 Structure_____________.__,_____,_____ .J::;,___L___ 39 General features.._______________-___ _____:.---___________________ 39 . Folds.________________________________________________________ 40 Faults -------__-__.-.___________________________________ 40 . Lenia fault.___________________ ____________^______________ 41 .: . Bull Lake fault,_______._______I_:__._.IJl'____,_______ 42 . .Savage Lake.fault__._._.____-_,_,. ____!_ _-i; ___________________ 44 : : .. O.'Bo-ien Creek fault____-^-_.__.____-1 iQ.'-J.- _ _ _-_--_______-__ 44 v i - - Snojvshoe fault. ______ _-_.^____._-^-_ _ _--____--_____._______ 45 . ; .. - Rock .Lake fault___^________-__________-_____-__-________ 45 il ._Hope fault____._._____._.___^________________-_^______________ 46 r,: Summary of structure__._-,._____^____^_^__________________-_____. 47 t,..; Age. of .folds, and faults-__.__--_^__-_^-^__-__--____---_--__-__--_ 49 Pleistocene.glaciation,. by. William_C. Alden___________________________ 49 Physiography, by J..T. Pardee____-_____^__________________________ 61 .Geologic history_._-___._____.______.__________"_______________________ 66 .Ore deposits._____________________________-_:__ -____^______________ 67 History .of. mining and.output-___----_-_____ _________________ 67 Outlook.for mining.__.__.___________^_____'_____________________ 69 ;:. Classification.,..._.__,..._._,_________________'__._.._..____.._. 71 . Distribution._.___________________..____: ____-_ _--__---_---_---. 71 Geologic relations of the.lodes. _______________ _ _____________L__ 72 Placer deposits_.__.___.___.____-____- -._- _---- = J.^--.--------------- 72 . ...jSAur.ce.of,the.gold_..____._.__.___._._...__.__. ___-_ _-__._-.______ __ 73 GolcUquartz .veina___. ._ __.________'jLr^'_flU___"________'i.-'_--_------ «* ..' _ .Ass.o.ciated.country rock________ _---_-------_--^__------------' *7Q ** c .^iructure and general character..________,; J^...:. _-__..... 74 _ _ Mineralogy- _ _._.__ ______ _._ _ _______, _- ^---------------------- 76 iU _Xetior__._.__________-.__--._.___-.-------- r -_:--^--- -- 78 :Sr, 'i SiLv.errlead. veins _._ _ _ __ _ _ _ - - ----- _-_ _ --- - -_^--_--_---------. 78 i.'!* ...Yeans.in sedimentary rocks.__._--_.__-^ _-_-_.----.----J!-__-__ 78 ^Yeins in dikes_-_________________________--_-__-_--__--_-_- 79 Veins in sills_____-_-_____-_________-_______-__--_---___--_ 80 Mineralogy.______________________________________________ 80 CONTENTS V Ore deposits Continued Page Copper veins ____________________________________________-_ -' 80 Origin of .the ores_ ---------.---------...-..---..---.......... 81 Mines and prospects. ......^...^............... ________________ 83 Gold-quartz.mines and prospects.___^_________._____________ 83 Fisher Creek__________________________________________ 83 Golden West Mining Co______________________________ 85 Little Annie._____________________________________ 85 New_.___.._.__ ........ ______________________ 86 Midas_______________________._______ 86 Tip Top-______________________________ 88 Gold HilL___.________________________________________ 89 American Kootenai.___________________________________ 90 Fourth of July.___________________________ 90 Herbert._____________________________ 90 Montezuma__ _______________________________________ 91 Mustang. ____________________ ______________________ 91 Way Up____ _ ______ . _____ _ ___________ 92 Williams. _____________.___..___________ 92 Betty Mae_-_--_-_--_.-_____....................... 93 Blue Bird and Maybe__________.__._----_______ 94 Diamond John._______________________________________ 94 Illinois-Montana. _____________________________________ 94 Irish Boy and Rambler_______________________________ 95 Libby___________________...___________ 95 Olsen and Switzer_-________i________________-_________ 96 Dome..._______-________-_____________ 96 Golden Bear___________ ------- __.'__.._____ 96 Sunrise-_-____----_-___---___-_-_-_-______-__----__.-_ 96 Silver-lead mines and prospects________________ _ _________ 97 Grouse Mountain-Callahan Creek area._.___---_--__-____ 97 Snowstorm _______._________ __________.___________ 97 Big Eight________________ _ __ _ ________ 100 Big Four.___________________________ 101 Giant Sunrise. ..............j..................... 101 Grouse Mountain________________________________ 102 Iron Mask...________________________ 103 Silver King___________________________________ 104 Liberty Metals__ .................................. 105 Bimetallic.._____...__________________ 106 Black Horse...______________________ 106 Blue Bird......._________________________________ 107 Cabinet Queen. .-...-....^-....................... 107 Hiawatha__ ____________________________________ 107 Little Spokane.--.__...___.-._____..._- 107 Silver Strike.___________.,___._______ 108 Universal.________________________________________ 108 American Eagle.__________________________________ 108 BlacktaiL. __________________________ 109 Keeler Mountain._________________________________ 109 Montana Morning.__.___________________________ 109 Silver Grouse._____----____._____-___---____---__- 110 VI CONTENTS Ore deposits Continued Mines and prospects Continued Silver-lead mines and prospects Continued . Snowshoe fault area_________________________________ 110 Snowshoe__ --___________-___--_-___-_-_-_---____ 110 Glacier Silver-Lead.__.-_______._.._-_______-__ 112 Silver Mountain_________________________________ 113 Montana Silver-Lead._____________________________ 113 Victor-Empire__